This was also posted on Spigot Hey guys, I've been trying to code a world management mod allowing users to separate different worlds into groups of worlds such as overworld, nether, and end. I've been recently running into errors where Bukkit seems to not recognize other worlds even though they are present within the server folder. The first error that happens is when getConfig() is called. The first time this happens, if there is a last known location for a player in any world other than the "main" world, then an error is thrown saying that the method failed to deserialize the location object because of an unknown world. It then erases the location object. To me, it seems that Bukkit is not recognizing any world other than the main world because all of the location objects are erased other than that of the main world. The second error that has recently started happening seems to be similar. When the tpworld command is entered, an exception is thrown saying that Bukkit.getWorld(String) returns null. This doesn't make any sense because I've verified that the string being passed is the correct name of the world. I need some help here. It seems like these errors are very similar, because both deal with Bukkit being unable to correctly load or recognize worlds. Any help would be appreciated. I've also included all the necessary files.